The objective of this proposal is to assess the biochemical basis for the deleterious effects of oxidant air pollutants. This problem will be approached by evaluating a number of different aspects of ozone toxicity including: 1. Development of assay systems capable of detecting microchemical amounts of carbonyl compounds produced by the breakdown of unsaturated fatty acids. 2. Investigation of the possibility that prolonged exposure to photochemical air pollution results in an increase in lung lipofuosin pigment consistent with an acceleration of the aging process. 3. Use of membrane probes to obtain information concerning the effects of ozone on the internal milieu of cell membranes. 4. Evaluation of possible molecular mechanisms whereby ozone might participate in carcinogenesis. 5. Assessment of the role of cytochrome P-450 in ozone toxicity and in the development of tolerance. 6. Determination of whether ambient levels of ozone are capable of oxidizing glutathione to glutathione sulfonic acid. 7. Evaluation of the possibility that ozone damages cell membranes so as to potentiate the effects of the alternate pathway of complement thereby leading to histamine release. Where feasible, these studies will also be performed following exposure to nitrogen dioxide and peroxyacetylnitrate.